Wall wart dc/dc power supply

[docnjoj]

One of U genius EEs came up with the idea, but I remembered it when my 12 volt dc/dc power supply failed on my trike. No lights. Also I foolishly wired 3 devices (2 white leds and a red flasher) in series cause they were each 3-4 volts and it worked for a while. So I found this old cell phone charger and wired in to the 42 volt batt and LO the light appeared. Now also I can wire parallel so I can actually know which device failed. Actually when I tested them individually they all workd fine! Including the 12 volt Power supply!! Much easier to trace parallel circuits! Duh! At least the new power supply is free!
otherDoc

 

[John in CR]

Doc,

Do I understand correctly, you gave a 120v AC walwart 42v DC and it still puts out 12vdc? If it's really that easy, I love it!

John

 

[Link]

No. I'm pretty sure he means something like a power brick (like what you charge your laptop with). Most wall warts are just transformers and sometimes rectifiers. The just look like a light resistive load to a DC source, so all it would do is get really hot if not fry.

 

[docnjoj]

Nah Link! I DO mean Wall wart! It was a switching power supply! The flat cell phone chargers will take a/c or d/c and convert it! This particular one came from a Motorola cell phone and claimed 100-220 input and 5v out! I think Fechter originally came up with it, but it does work! Ill post pics tomorrow! It does put out 5V which allows me to wire my lights in parallel!!
otherDoc

 

[nasukaren]

No. I'm pretty sure he means something like a power brick (like what you charge your laptop with). Most wall warts are just transformers and sometimes rectifiers. The just look like a light resistive load to a DC source, so all it would do is get really hot if not fry.

The switching ones are the best since they're essentially a rectifier (to get DC) and then a switching power supply like a buck converter. So they don't care what type of dirty power or AC/DC they get. Lots of the automobile EV folks use 120 VAC --> 14 VDC laptop switching power supplies for their low power systems.

Look on the back of the wall wart. If it can take 120-240 VAC and 50/60hz, then chances are its a switching supply and can take DC. If it can only take 120 VAC @ 60 hz, then it's a little transformer and may be unhappy.

K

 

[docnjoj]

Its the real thing! 120-220!@50-60 Hz!
OtherDoc

 

[Link]

Nah Link! I DO mean Wall wart! It was a switching power supply! The flat cell phone chargers will take a/c or d/c and convert it! This particular one came from a Motorola cell phone and claimed 100-220 input and 5v out! I think Fechter originally came up with it, but it does work! Ill post pics tomorrow! It does put out 5V which allows me to wire my lights in parallel!!
otherDoc

Yeah, I know what you mean (I have one for mah Game Boi ), but they're mostly found as a brick in the middle of the cord. I don't know why...:?

 

[TylerDurden]

but they're mostly found as a brick in the middle of the cord. I don't know why...:?

Size, meethinks.

 

[Patriot]

I bought one of these from http://www.project-parts.com

I can't wait to give it a try. Only $25. Not bad for the size and 100w power output.

It has 3 outputs. 2-12Vdc if you run halogens, and 1-3.3Vdc rated up to 30amps, for LED's or cyclocomputer. etc.

 

[docnjoj]

Powerstream Tech sells those. I think it was 12 bucks plus shipping about a year ago. Its in my wifes bike.
otherDoc